The invention relates to a spring support for a motor vehicle, to the use of the spring support and to the production of a spring support for a motor vehicle.
In order to connect a spring-damping unit of a front axle, bodywork structures are known in which a spring support is produced from a plurality of steel plates, and a spring strut cup composed of steel is welded to a plurality of shell components composed of steel, which have connections to an engine bracket and to a supporting bracket. Due to the high dead weight of the steel, bodywork structures composed of lighter materials have more recently been provided. For example, spring supports which are produced from light metal in a die cast structure are known. However, the light metals used here lead in combination with a bodywork structure composed of even lighter carbon fiber composite plastic (CFP) to contact corrosion and problems due to the different coefficients of thermal expansion of the light metals in comparison to CFP and steel.
On the basis of this prior art, it is therefore the object of the present invention to provide a spring support for a motor vehicle, which spring support, firstly, satisfies the high mechanical requirements of a spring support, and secondly, avoids contact corrosion and problems due to different coefficients of thermal expansion, but nevertheless has only a low weight. Furthermore, it is the object of the invention to provide a simple and cost-effective method for producing a spring support which is stable, is nevertheless very light, is protected against corrosion and is protected from problems based on different coefficients of thermal expansion.
This and other objects are achieved according to the invention in the case of a spring support for a motor vehicle in that a spring strut cup composed of a metallic material, and three shell components composed of a fiber composite material, in particular a fiber-reinforced plastic, are provided, wherein the spring strut cup is connected in the shell components in such a manner that: (i) a first shell component spans an arc from an outer side of an engine bracket to a lower side of a support bracket, and the spring strut cup is fastened at the edge thereof from below to the first shell component, (ii) a second shell component connects an upper side of the supporting bracket, an upper side of the first shell component and an outer upper side of the spring strut cup to one another, and (iii) a third shell component is fastened to an inner side of the engine bracket and to an upper side of an engine bracket and to an inner side of the first shell component and an inner upper side of the spring strut cup.
By forming the spring strut cup from a metallic material, the latter can be stably screwed to a supporting bearing of a spring suspension, for example a front axle spring suspension. Owing to the fact that the spring strut cup is connected in a specific manner to three shell components composed of a fiber composite material, and the fiber composite materials provide a secure bond with the surrounding motor vehicle parts, for example an engine bracket and a supporting bracket, which are likewise preferably formed in a fiber composite construction (for example CFP), contact corrosion and problems due to different coefficients of thermal expansion can be effectively averted. In addition, weight is effectively reduced by using shell components in a fiber composite construction, with consistently good mechanical properties. By means of the specific arrangement and geometry of the individual components, the spring strut cup is embedded twice in the pressure direction in the surrounding shell components, and therefore the connection thereof is predominantly subject to compression loading. The composite construction according to the invention composed of metallic material and fiber composite materials is therefore distinguished by excellent stability with a high weight saving.
According to an advantageous development, the fiber composite material forming the shell components is a carbon fiber composite material, in particular a carbon fiber reinforced plastic (CFRP). Carbon fiber composite materials are distinguished by a very low dead weight with very good mechanical properties.
For a permanent connection of the shell components and the spring strut cup, it is furthermore advantageous that the spring strut cup and the shell components are connected to one another by use of adhesive bonding. This is furthermore beneficial for stability against corrosion. By means of the preferably sheet like adhesive bond along the respective connecting surfaces, a connection is provided which is sufficiently stable to pressure and withstands even high mechanical loads of that type that act on a front axle of a motor vehicle.
In a further advantageous development, the spring strut cup, the first shell component and the second shell component are connected to one another in such a manner that a substantially rectangular profile is formed between an outer side of the spring strut cup, an inner side of the supporting bracket, the first shell component which is joined from below to the supporting bracket and the second shell component which is connected to the upper side of the supporting bracket. This is of advantage for a uniform transmission of force, and therefore the spring support according to the invention is resistant even to high mechanical actions.
In order to further increase the stability of the spring support according to the invention, the first shell component and the third shell component together form a substantially vertical profile which is closed at the upper end thereof by the spring strut cup and at the lower end thereof by the engine bracket.
The use of the above-described spring support for a motor vehicle for the connection of a spring-damper unit of a front axle, preferably a McPherson front axle, is likewise described according to the invention. Owing to the specific geometry of a McPherson front axle, the spring support according to the invention is particularly readily suitable for this purpose.
Furthermore, a method for producing a spring support for a motor vehicle is described according to the invention, which method is characterized by the following acts: (i) providing a spring strut cup composed of a metallic material, and three shell components composed of a fiber composite material, in particular a fiber-reinforced plastic, (ii) fastening a first shell component to an outer side of an engine bracket and to a lower side of a supporting bracket such that the first shell component spans an arc, (iii) fastening an edge of the spring strut cup from below to the first shell component, (iv) connecting a second shell component to an upper side of a supporting bracket, an upper side of the first shell component and an outer upper side of the spring strut cup, and (v) fastening a third shell component to an inner side of an engine bracket and an upper side of an engine bracket and to an inner side of the first shell component and an inner upper side of the spring strut cup.
By use of the method according to the invention, in particular by use of a combination of specific materials for a spring strut cup and shell components for fastening to correspondingly provided motor vehicle parts with a specific geometry, arrangement and manner of fastening the shell components, an advantageous spring support is provided for a motor vehicle in a simple and cost-effective manner without a high technical outlay. The spring support is corrosion-resistant, is protected from problems with different coefficients of thermal expansion and is stable and is likewise distinguished by a significantly weight-reduced construction.
The advantageous effects, advantages and refinements described for the spring support according to the invention for a motor vehicle are also applied to the method according to the invention for producing a spring support for a motor vehicle. It should furthermore be mentioned that the method according to the invention is also suitable for producing the above-described spring support.
In order to ensure a permanent bond between the provided components of the spring support and in order, furthermore, to avoid contact corrosion, the spring strut cup and the shell components are adhesively bonded to one another.
In order to provide a uniform transmission of force during operation of the spring support such that the spring support is resistant even to high mechanical effects, the method according to the invention is furthermore characterized in that the spring strut cup is joined to the first shell component, which is joined from below to the lower side of the supporting bracket, and the second shell component is joined from above to the upper side of the supporting bracket and to the spring strut cup. Therefore, a substantially rectangular profile is formed between an outer side of the spring strut cup, an inner side of the supporting bracket, the first shell component, which is joined from below to the supporting bracket, and the second shell component, which is connected to the upper side of the supporting bracket.
By way of the further advantageous refinement that the third shell component together with the first shell component forms a substantially vertical profile which is closed at the lower end thereof by the engine bracket and at the upper end thereof by the spring strut cup, the stability of the spring support can be further increased.
As a result of the refinements and developments of the spring support according to the invention for a motor vehicle and of the method according to the invention for producing a spring support for a motor vehicle, in particular the following advantages are afforded:
(1) the mechanical properties of the spring support are improved by the selection according to the invention of the materials in combination with the designated geometry and arrangement of the components,
(2) the bond between the shell components and the spring strut cup is stabilized,
(3) the weight of the spring support according to the invention is lower, with the same functional properties, than in the case of spring supports produced in a conventional construction,
(4) the spring support is effectively protected against contact corrosion,
(5) problems due to different coefficients of thermal expansion are avoided,
(6) the method can be realized in a simple manner without a high technical outlay and therefore cost-effectively.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.